package org.apache.lucene.index;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;

import org.apache.lucene.util.AttributeSource;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;

/** This is a DocFieldConsumer that inverts each field,
 *  separately, from a Document, and accepts a
 *  InvertedTermsConsumer to process those terms. */

final class DocInverterPerThread extends DocFieldConsumerPerThread {
    final DocInverter docInverter;
    final InvertedDocConsumerPerThread consumer;
    final InvertedDocEndConsumerPerThread endConsumer;
    final SingleTokenAttributeSource singleToken = new SingleTokenAttributeSource();

    static class SingleTokenAttributeSource extends AttributeSource {
        final CharTermAttribute termAttribute;
        final OffsetAttribute offsetAttribute;

        private SingleTokenAttributeSource() {
            termAttribute = addAttribute(CharTermAttribute.class);
            offsetAttribute = addAttribute(OffsetAttribute.class);
        }

        public void reinit(String stringValue, int startOffset, int endOffset) {
            termAttribute.setEmpty().append(stringValue);
            offsetAttribute.setOffset(startOffset, endOffset);
        }
    }

    final DocumentsWriter.DocState docState;

    final FieldInvertState fieldState = new FieldInvertState();

    // Used to read a string value for a field
    final ReusableStringReader stringReader = new ReusableStringReader();

    public DocInverterPerThread(DocFieldProcessorPerThread docFieldProcessorPerThread, DocInverter docInverter) {
        this.docInverter = docInverter;
        docState = docFieldProcessorPerThread.docState;
        consumer = docInverter.consumer.addThread(this);
        endConsumer = docInverter.endConsumer.addThread(this);
    }

    @Override
    public void startDocument() throws IOException {
        consumer.startDocument();
        endConsumer.startDocument();
    }

    @Override
    public DocumentsWriter.DocWriter finishDocument() throws IOException {
        // TODO: allow endConsumer.finishDocument to also return
        // a DocWriter
        endConsumer.finishDocument();
        return consumer.finishDocument();
    }

    @Override
    void abort() {
        try {
            consumer.abort();
        } finally {
            endConsumer.abort();
        }
    }

    @Override
    public DocFieldConsumerPerField addField(FieldInfo fi) {
        return new DocInverterPerField(this, fi);
    }
}
